output (CO)/cardiac index: measured using the thermodilution technique (reliability of measurement is affected by tricuspid or pulmonary regurgitation or intracardiac shunts):Normal CO: 4–8 L/min.Normal CI: 2.5–4 L/min/m2.
Calculated measurements
Stroke volume (SV) = CO/HR:Normal: 60–120 mL/beat.
Systemic vascular resistance (SVR) = 80 × [(MAP – RAP)/CO]:Normal: 1600–3000 dyn·s/cm5.
Pulmonary vascular resistance (PVR) = 80 × [(mean PAP – mean PAWP)/CO]:Normal: 37–250 dyn·s/cm5.
Complications
Rates of 5–10%.
Bleeding, hematoma, arterial puncture/cannulation, pneumothorax, hemothorax, tachyarrhythmias, right bundle branch block, complete heart block, pulmonary artery rupture, myocardial perforation, infection.
Echocardiography
Ultrasound echocardiography is an operator‐dependent hemodynamic assessment, which is a quick and non‐invasive measurement tool. Its effectiveness has not yet been proven in randomized clinical trials.
Cardiac function and anatomy can be assessed using five standard views (Table 11.2).
Stroke volume can be estimated with echocardiography:SV = π × R2 × velocity time interval (VTI) of the left ventricular outflow tract (LVOT) (R= radius of LVOT in cm).Parasternal long axis view is used to measure diameter of the LVOT.Apical five chamber view is used to measure the VTI with pulsed Doppler.
Routine measurements of the size of the IVC and collapsibility with respiration can be used to estimate right atrial pressure (RAP) and fluid responsiveness in patients via the subcostal view on echocardiography.
Size ≤2.1 cm, collapses >50% during inspiration = RAP 0–5 mmHg.
Size >2.1 cm, collapses >50% during inspiration = RAP 5–10 mmHg.
Size >2.1 cm, collapses <50% during inspiration = RAP 10–20 mmHg.
Table 11.2 Echocardiography views.
| View | Findings |
|---|---|
| Parasternal long axis | Pericardial effusion, LV/RV size and function, septal kinetics |
| Parasternal short axis | Pericardial effusion, LV/RV size and function, septal kinetics |
| Apical four chamber | Pericardial effusion, LV/RV size and function |
| Subcostal four chamber | LV/RV size and function, preferred view in cardiac arrest |
| Inferior vena cava longitudinal view | Determine preload sensitivity |
Reading list
1 Bolt, J. Clinical review: hemodynamic monitoring in the intensive care unit. Crit Care 2002; 6:52–9.
2 Conners AF, et al. The effectiveness of right heart catheterization in the initial care of critically ill patients. JAMA 1996; 276:889–97.
3 Greenstein YY, Mayo PH. Critical care echocardiography. In: Oropello JM, Kvetan V, Pastores SM (eds) Critical Care. New York: McGraw‐Hill, 2017, pp. 1141–50.
4 Leatherman JW, Marini JJ. Clinical use of the pulmonary artery catheter. In: Hall JB, Schmidt GA, Wood LDH (eds) Principles of Critical Care, 2nd edition. New York: McGraw‐Hill, 1998, pp. 155–76.
5 Mark JB. Central venous pressure monitoring: clinical insights beyond the numbers. J Cardiothorac Vasc Anesth 1991; 5:163–73.
6 Monnet X, Teboul JL. Minimally invasive monitoring. Crit Care Clin 2015; 31:25–42.
7 Porter TR, et al. Guidelines for the use of echocardiography as a monitor for therapeutic intervention in adults: a report from the American Society of Echocardiography. J Am Soc Echocardiogr 2015; 28:40–56.
8 Weiner R, Ryan E, Yohannes‐Tomicich J. Arterial line monitoring and placement. In: Oropello JM, Kvetan V, Pastores SM (eds) Critical Care. New York: McGraw‐Hill, 2017, pp. 1085–92.
9 Yunen RA, Oropello JM. Pulmonary artery catheterization. In: Oropello JM, Kvetan V, Pastores SM (eds) Critical Care. New York: McGraw‐Hill, 2017, pp. 1245–61.
Figure 11.1 Arterial pressure waveforms at different locations in the vascular tree.
Figure 11.2 Components of the CVP waveform throughout the cardiac cycle.
Figure 11.3 Placement of a pulmonary artery catheter. At different depths of catheter placement different waveform profiles will be identified.
Additional material for this chapter can be found online at:
www.wiley.com/go/mayer/mountsinai/criticalcare
This includes multiple choice questions.
CHAPTER 12 Vasoactive Drugs
Ajay S. Vaidya1 and Umesh K. Gidwani2
1 Keck School of Medicine of USC, Los Angeles, CA, USA
2 Icahn School of Medicine at Mount Sinai, New York, NY, USA
OVERALL BOTTOM LINE
Verify the patient’s blood pressure yourself.
Think
